Since the macro AST is built as a custom tokenizer inside the system, it needs access to the import set. On the other hand, import sets aren't available until after parsing. Need a way to place this order in a lexer without restricting the expression value of the lexer.

The daft option of accepting import resolution queries at runtime is available but consider better options.

## alternate extension mechanism

The STD system will have a lot of traffic for trivial operations like algebra, stream IO will likely not be fast enough. A faster system is in order.

Ideally, it should reuse `orchid-extension` for message routing and decoding.

`orchid-host` accepts extensions as `impl ExtensionPort`

## Preprocessor extension

The macro system will not be privileged, it can take control from the interpreter via a custom top-level "let" line type.

Must actually write macro system as recorded in note

Check if any of this needs interpreter, if so, start with that